I would like to build the three types of JPL Mars rovers (Sojourner, MER and MSL) with the right size ratio relative to each other. For that, finding the right wheels would be the hardest thing. I can build the rest of the robots as long as I know the wheels will have the right look.

Here's a pictures of the three wheel types:

Important Notes:

The overall size doesn't have to be at the scale of the minifigures. Even though this would be really cool, it would turn the Sojourner project into a micro build. This would be much harder.

The look of the wheel hubs is not relevant. What is important is the look/ratio of the tire's outside dimensions. Note that Sojourner's wheel (the small one) has a flat rolling surface while the others two are rounded.

Edit: The medium wheel is (appropriately) 1.8x the size of the small wheel while the big wheel is (appropriately) 1.7x the size of the medium wheel.

Here's what found after playing with all kinds of combinations. With this the three rovers will be at the same scale (about 1:5.8). This scale is small enough that the big rover (MSL) would not be a monster to build.

The ratio is almost spot on and the only main problem is that the MSL wheels (the big ones) will have those big cleats.

On the positive side, they all have the right shape. Only the medium wheels have that bulgy look while the other two have a flatter driving surface.

I'm only missing 1 wheel (2x 64711) for the MSL rover so I'll order that online. It won't slow me down too much since I'll start with the small rover and build my way up. I'll probably document the build (or show the result) on my blog.
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pcantinJun 17 '12 at 11:57

Thanks for the links. I'll dig around on Brinklink to see if I can find the right combination of sizes(ratio) and of looks. I'm also interested in the full wheel-tire BTW (not only the wheels).
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pcantinJan 15 '12 at 1:14